1. Field of the Invention
The invention relates to a method of driving a subfield-driven display, and to a subfield-driven display apparatus.
2. Description of the Related Art
In plasma display panels (PDPs) or other subfield-based display devices, motion artifacts are present due to the way gray-scales are made. Furthermore, motion compensation is applied in PDPs to reduce motion artifacts. The artifacts are caused by the way our eyes perceive motion by tracking a moving object. This results in the situation that more pixels at various moments are combined in the gray-scale that is observed during motion tracking. Due to the way, gray-levels are made on a PDP (and DMD), various subfields of various pixels contribute to the gray-level that is being observed. This can results in xe2x80x9cdynamic false contoursxe2x80x9d, i.e. small changes in luminance (an object that is moving with a gradual changing gray-level or color) can result in large changes in luminances. Motion compensation can be used to reduce this error. In natural sequences objects are moving in various directions with various speeds. Due to the way motion compensation is implemented, a problem arises on the border of the speed variations, i.e. the areas of covering and uncovering. Therefore, some measures must be taken to prevent artifacts at these borders.
It is, inter alia, an object of the invention to provide a motion compensation having reduced covering and uncovering artifacts. To this end, the invention provides a method of driving a subfield-driven display and a subfield-driven display apparatus.
In a method of driving a subfield-driven display (PDP) in accordance with a primary aspect of the present invention, for a position in a subfield it is examined whether a motion vector for the position differs from a motion vector for a neighboring position to determine whether uncovering or covering is present. If uncovering or covering is present, a size of an area of covering and uncovering is calculated, and the area of covering and uncovering is filled in.
Preferably, the solutions are intra-field methods to overcome the covering/uncovering artifacts as intra-field methods are easier to implement (no field memories are required).